TEM photographs of ZrO2, Pd/ZrO2, ZrO2–CS, and Pd/ZrO2–CS in Fig. 2 showed a very serious agglomeration of ZrO2 nanoparticles while ZrO2–CS primary particles were relatively uniform. It holds also true for Pd/ZrO2 and Pd/ZrO2–CS nanoparticles where Pd was dispersed over uniform ZrO2 nanoparticles. It reflects the role of CS in the distribution uniformly of ZrO2 and Pd/ZrO2 nanoparticles.